include/core/framerate.hpp

   1 #ifndef _framerate__hpp__included__
   2 #define _framerate__hpp__included__
   3
   4 #include <cstdint>
   5 #include "library/threads.hpp"
   6
   7 #define FRAMERATE_HISTORY_FRAMES 10
   8
   9 /**
  10  * Framerate regulator.
  11  */
  12 class framerate_regulator
  13 {
  14 public:
  15         framerate_regulator();
  16 /**
  17  * Set the target speed multiplier.
  18  *
  19  * Parameter multiplier: The multiplier target. May be INFINITE.
  20  */
  21         void set_speed_multiplier(double multiplier) throw();
  22
  23 /**
  24  * Get the target speed multiplier.
  25  *
  26  * Returns: The multiplier. May be INFINITE.
  27  */
  28         double get_speed_multiplier() throw();
  29
  30 /**
  31  * Sets the nominal frame rate. Framerate limiting tries to maintain the nominal framerate when there is no other
  32  * explict framerate to maintain.
  33  */
  34         void set_nominal_framerate(double fps) throw();
  35
  36 /**
  37  * Returns the current realized framerate multiplier.
  38  *
  39  * returns: The framerate multiplier the system is currently archiving.
  40  */
  41         double get_realized_multiplier() throw();
  42
  43 /**
  44  * Freeze time.
  45  *
  46  * Parameter usec: Current time in microseconds.
  47  */
  48         void freeze_time(uint64_t usec);
  49
  50 /**
  51  * Unfreeze time.
  52  *
  53  * Parameter usec: Current time in microseconds.
  54  */
  55         void unfreeze_time(uint64_t usec);
  56
  57 /**
  58  * Acknowledge frame start for timing purposes. If time is frozen, it is automatically unfrozen.
  59  *
  60  * parameter usec: Current time (relative to some unknown epoch) in microseconds.
  61  */
  62         void ack_frame_tick(uint64_t usec) throw();
  63
  64 /**
  65  * Computes the number of microseconds to wait for next frame.
  66  *
  67  * parameter usec: Current time (relative to some unknown epoch) in microseconds.
  68  * returns: Number of more microseconds to wait.
  69  */
  70         uint64_t to_wait_frame(uint64_t usec) throw();
  71
  72 /**
  73  * Return microsecond-resolution time since unix epoch.
  74  */
  75         static uint64_t get_utime();
  76
  77 /**
  78  * Wait specified number of microseconds.
  79  */
  80         void wait_usec(uint64_t usec);
  81 /**
  82  * Turbo flag.
  83  */
  84         bool turboed;
  85 private:
  86         uint64_t get_time(uint64_t curtime, bool update);
  87         double get_realized_fps();
  88         void add_frame(uint64_t linear_time);
  89         std::pair<bool, double> read_fps();
  90         uint64_t last_time_update;
  91         uint64_t time_at_last_update;
  92         bool time_frozen;
  93         uint64_t frame_number;
  94         uint64_t frame_start_times[FRAMERATE_HISTORY_FRAMES];
  95         //Framerate.
  96         double nominal_framerate;
  97         double multiplier_framerate;
  98         threads::lock framerate_lock;
  99
 100 };
 101
 102 #endif